The '''United States Department of War''', also called the ''War Department'' (and occasionally ''War Office'' in the early years), was the United States Cabinet
department originally responsible for the operation and maintenance of the United States Army
, also bearing responsibility for naval affairs until the establishment of the United States Department of the Navy|Navy Department
in 1798, and for most land-based air forces until the creation of the United States Department of the Air Force|Department of the Air Force
on September 18, 1947.
The United States Secretary of War|Secretary of War
, a civilian with such responsibilities as finance and purchases and a minor role in directing military affairs, headed the War Department throughout its existence.
The War Department existed from August 7, 1789